Skeptical members of Congress are heading to the White House today for a classified full-court press by President Obama and his advisers who will try to convince them to back a military strike on Syria in retaliation for a chemical weapons attack that the U.S. said killed hundreds of civilians — an effort one local congressman called “an uphill battle.”

South Boston U.S. Rep. Stephen F. Lynch will be among those going to Washington, D.C., for the briefing after Obama yesterday said he had decided the U.S. should take military action against Syria but he would seek a Congressional vote to authorize the attack. But Lynch says it’s going to be a tough sell for him and the lawmakers he’s consulted.

“Personally I’m highly reluctant to support military action in Syria. However, I think I owe it to the president to listen to his case, and I think that’s pretty much the position my colleagues will take,” Lynch said. “But I think there’s significant resistance to going in militarily.”

Lynch said his reluctance comes from the fact that rebel forces opposing Syrian President Bashar Assad’s regime are supported by al-Qaeda, and most of the United State’s allies are sitting out the conflict.

“I don’t understand why the United States should do this unilaterally,” he said.

Obama yesterday argued that “this menace must be confronted,” but Lynch is not sure that will sway enough lawmakers.

“It’s an uphill fight for the president,” he said.

U.S. Rep. James McGovern of Worcester said he has many questions about Obama’s plan of action.

“Is this just to punish Assad or is there a long-term strategy?” asked McGovern. “I think a lot of people feel as I do. This is not necessarily the right way to go.”

Congress was not expected to return to Washington until next week, but Lynch said senators and representatives are being recalled for high-level briefings and he expects the vote will be moved up. “I think they’re trying to collapse the time frame,” he said.

Boston University presidential scholar and foreign policy expert Thomas Whalen predicted Obama will win in Congress in a squeaker of a vote. He said the administration blundered by not releasing intelligence damning the Assad regime before a similar, unsuccessful, vote in the British Parliament.

“Certainly this potentially puts the onus on Congress now and takes the heat off President Obama,” Whalen said.

Brookings Institution scholar Elaine Kamarck, a former top Clinton White House aide, said second-term presidents look more toward their legacy than political gain, so internal White House discussions are likely more about the success or failure of an attack than domestic political acceptance.

“Having been a part of some discussions like this, my guess is one of the biggest questions on everyone’s minds would be if it’s worth it. Would (proposed attacks) have the impact the president wants to have,” Kamarck said. “Public opinion is secondary to the larger question, will this work? … If it doesn’t work, it will not look so good for the president. If it does work, it will be a big part of his legacy.”